Sheet bending machine for producing tubular elements and plant including applicationof said machine



Oct. 9, 1962 G. J. J. VUILLIEN 3,057,394

SHEET BENDING MACHINE FOR PRODUCING TUBULAR ELEMENTS AND PLANT INCLUDING APPLICATION OF SAID MACHINE Filed May 2, 1960 5 Sheets-Sheet 1 h /g f-or: wrges Tea. fiSerA VuiLuE/v Oct. 9, 1962 G. J. J. VUILLIEN 3,057,394

SHEET BENDING MACHINE FOR PRODUCING TUBULAR ELEMENTS AND PLANT INCLUDING APPLICATION OF SAID MACHINE Filed May 2, 1960 3 Sheets-Sheet 2 7m an F0 r,- [ear 6 MM Oct. 9, 1962 G. J. J VUILLIEN SHEET BENDING MACHINE FOR PRODUCING TUBULAR ELEMENTS AND PLANT INCLUDING APPLICATION OF SAID MACHINE. Filed May 2, 1960 5 Sheets-Sheet 3 ouvanf r' 01.0! g; J ark UI'LLI'EN A- Ho'rm & MU

mail- The present invention relates to sheet metal bending machines for producing tubular elements and more particularly to hydraulic machines in which these elements are formed from a flat rectangular sheet of metal whose dimensions correspond to those of the tubular element to obtain by applying this sheet against an anvil in a direction parallel with its longitudinal edges by means of a suitable tool operating by successive blows.

Known machines or hydraulic presses comprise a lower anvil whose length corresponds to that of the tube to obtain and which could have a concave curvature and a bending device which is disposed above the anvil and has a punch whose length corresponds to that of the tube to obtain and is vertically movable. The anvil and the bending actuating means are carried by a bolster device. The lower and upper bolsters are rigidly braced, for example by four uprights, the assembly constituting a closed press frame or cage. The stifiening arrangements for the anvil and above all the single bending device of great length (about several metres) make the machine particularly heavy owing to the reinforcement of the upper bolster and the corresponding proportions of the lower bolster.

When these machines are designed to produce tubes of large diameter and great thickness, they take up a great amount of space particularly in height not only due to the necessary bending force and consequently the size of the raws, but also due to the size of the maximum diameter of the tubes to form. The great height of the frame requires a reinforceing thereof in width, whence increased weight and overall size. The dimensions of these machines therefore become prohibitive.

The object of the invention is to provide a hydraulic bending machine improved in such manner as to permit without excessively dimensions the production of thick, very large diameter tubular elements.

This machine mainly comprises a multiple press having on a single stand, a number of elementary presses whose swan-neck shaped frames are in alignment in a direction perpendicular to a fixed direction in which the metal sheet is fed, a single anvil rigidly suspended from the upper parts of said frames by a single flat plate which almost completely closes the opening of said swan-neck shaped frames and constitutes an axial plane of symmetry of said anvil whose operative face is, in the same way as said plane, transverse to the direction in which the metal sheets are fed and is downwardly directed, the stand carrying in front of each frame a hydraulic actuating device actuating an individual bending device, the hydraulic devices and the bending devices pertaining to the different elementary presses being in alignment parallel with said plane of symmetry, that is, transversely of the longitudinal direction in which the metal sheets are fed.

Owing to this arrangement and particularly to the 3,057,394 Patented Oct. 9, 1962 ice multiplicity of the press frames and the movable bending devices pertaining to the various elementary presses constituting the multiple press and owing to the mounting of these bending devices at the foot of the press frames, the surprising result is obtained that the machine according to the invention has, for a given power, much smaller dimensions than those of known machines and particularly as concerns its one height which is reduced by about one half. Further, this arrangement permits feeding the metal sheets in a horizontal plane which facilitates the handling of the sheets, whereas in known machines the sheets are fed in a plane downwardly inclined toward the striking plane.

Another object of the invention is to provide a plant for continuously producing tubular elements, which are welded along a longitudinal joint, this plant comprising two bending machines of the above-mentioned improved type, each one bending one half of each metal sheet.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings to which the invention is in no way limited.

In the drawings:

FIG. 1 is a diagrammatic side elevational view, with parts cut away, of a machine according to the invention, having presses, shown in their bending position, and a feed device;

FIG. 2 is a partial perspective view of the machine showing a number of its elementary presses combined with the single common anvil;

FIG. 3 is a partial side elevational view of one of the elementary presses in its inoperative position at the moment of arrival of the sheet to bend;

FIG. 4 is a vertical longitudinal section-a1 view, taken along line 44 of FIG. 2, of the sheet feed device;

FIG. 5 is a diagrammatic sectional view of the hydraulic press actuating device;

FIG. 6 is a view similar to FIG. 5 of the hydraulic device actuating the sheet feed device;

FIGS. 7 to 12 are diagrams showing different stages in the production of a tubular element;

FIG. 13 is a diagrammatic plan view of a complete plant for producing tubes comprising two bending ma? chines according to the invention, and

FIG. 14 is a diagrammatic view similar to FIG. 3 of a modification of the feed device feeding metal sheets whose longitudinal edges have been previously bent or formed up.

I. DESCRIPTION OF THE BEN'DING MACHINE (FIGS. 1 TO 6) In the illustrated embodiment, the machine is adapted to bend a metal sheet I along parallel generatrices so as to impart thereto a closed curve shape in the form of a tube and thereby bring together the opposite ends which are parallel with these generatrices and must be subsequently welded together.

This machine comprises mainly (FIG. 1): a multiple press A, its sheet feed device B feeding the sheets in a longitudinal direction from right to left as viewed in FIG. 1, parallel with the plane of the latter, a hydraulic actuating device C actuating the multiple press A, and a hydraulic actuating device D actuating the sheet feed device B. Each of these parts will be described in turn.

3 (a) Multiple Press A (FIGS. 1, 2 and It mainly comprises a number of elementary presses in transverse alignment over a distance which corresponds to the length of the tubes to produce; for example there are eight presses, only four of which are shown in FIGS. 2 and 5. These presses are mounted on a common stand 1 having an inclined face.

Each press comprises a frame 2 which has a V- or swan-neck shape. The frames are fixed to the stand 1. Fixed to the ends of the. heads 3 of the frames 2 is a plate 4 which is common to all the presses. This plate is relatively thin and in the form of a solid having an even resistance, its thickness decreasing downwardly. It almost completely closes the opening of the swan-neck shape of the frames in a plane XX (FIG. 2) which is inclined at an angle x to the vertical and downwardly approaches the frames 2. The angle x approximately corresponds to half the angle subtended by the arc of the bend produced in the metal sheet at each stroke of the press. The lower edge of this plate 4 rigidly supports a shoe 5 under which is detachably secured by screws 6 an interchangeable single anvil 7 which is thus rigidly suspended by the plate 4 from the heads 3 of the frame 2.

This anvil 7 has a lower operative face in the form of a sector of a cylinder whose radius corresponds to half the diameter of the tubes to be obtained and is symmetrical relative to the plane XX.

Each press furthermore comprises a hydraulic ram or jack V fixed to the stand 1 under the anvil 7. The axis of operation of each ram V is in the plane of symmetry XX and is therefore in the extension of the plate 4.

Each ram V is capable of being fed with oil under pressure by the device C either by way of a pipe S connected to its lower part or by way of a pipe S connected to its upper part and it includes a double-acting piston 10 supporting a slide 11 terminating in a flat slideway or guide 12 perpendicular to the plane XX.

Mounted on the slideway 12 is a pair of punches )13 and 13 which have a convex operative face and are symmetrical relative to the plane XX and whose spacing is adjustable by shifting them on the slideway 12. In the direction parallel with the plane XX each punch has a length corresponding to the length of the tube to be formed divided by the number of presses. The punches of the different presses located on the same side of the plane XX are in alignment. A 'very small gap is provided between the punches of adjacent presses. Each punch is adjusted separately by means of two screws 14 screw-threadedly engaged in nuts 15 fixed to the slideway 12. After adjustment, the punches are blocked in position on the slideway 12 by means of clamping bolts 16 To enable the machine to produce tubes of different diameters the appropriate anvil 7 is mounted and the punches 13 and 13 are so set at the suitable distance apart relative to the plane XX in accordance with the desired diameter that the maximum distance between the punches 13 and the plane XX is no greater than that between the generator a of the anvil and the plane XX.

(b) Metal Sheet Feed Device B (FIGS. 1 and 4) This device B comprises a feed table feeding the metal sheet t and constituted by parallel horizontal supports 17 which are perpendicular to the generatrices of the sector of a cylinder constituted by the anvil 7. The sheet of metal t-whose length corresponds to that of the tube to be produced and whose width corresponds to the circular perimeter of a cross-section of this tubeis placed on these horizontal supports 17 and the end of the sheet remote from the machine is subjected to a thrust in the direction of the press from two thrust 4 members or abutments 18 spaced apart a distance a little less than the length of the sheet t. Each of the members 18 is adjustably secured to a rack 19 provided with rollers 20 and 21 rolling along runways 22 and 25 parallel with the horizontal supports 17.

Each of the two racks 19 is meshed with a gear 24 carried by a shaft 25 whose axis is perpendicular to the racks 19. This shaft is driven in rotation by either of two electromagnetic clutches E and F, either in step by step manner in the direction of arrow f (corresponding to the advance of the racks toward the machine) by a ram or jack V (FIG. 1), or continuously in the opposite direction of arrow f (corresponding to withdrawal of the racks -19) by a motor and speed reducer unit C.

To this end, one end of the shaft 25 is provided with tfluting along which is slidable the secondary clutch plate of the electromagnetic clutch E whose primary plate is connected to a free wheel 26. The latter drives the primary plate of the clutch E only in the direction of arrow f corresponding to advance of the racks 19 toward the machine. The free-wheel 26 is itself driven in rotation by a gear 27 meshed with a rack 28 which is parallel with the racks 19 and fixed to one end of a rod 29 of the piston 30 of the ram V (FIG. 6). This piston has another rod 31 in opposed relation to the rod 29. The travel of the piston 30 corresponds to the length of the arc formed in the metal sheet at each stroke of the press and is limited at one end by an adjustable abutment 32, against which the rack 28 stops, and at the other end by a fixed abutment 33 which stops the rod 31. Connected to the ends of the cylinder of the ram are pipes 34 and 35 connected to the hydraulic actuating device D. The other end of the shaft 25 is provided with fiuting along which is slidable the secondary plate of the electromagnetic clutch F whose primary plate is driven in rotation by the motor and speed reducer unit G.

The clutch F and this unit are supplied with power in series by an electric circuit H to which the clutch E is branch connected. The supply of power to this clutch E is controlled by a switch I and that of the clutch F by a switch I. These switches are mechanically interconnected in such manner that when one of them is open the other is closed.

The purely mechanical part of the sheet feed device is completed by an abutment 36 (FIGS. 1, 3 and 4) for the leading or forward edge of the metal sheet t engaged in the machine. This abutment is disposed substantially mid-way between the racks 19 so as to be in the middle of the leading edge of the metal sheet and is, in the presently-described embodiment, constituted by one arm 36 of a bell crank pivotably mounted at 37 on one of the press frames 2. The other arm 38 of this bell crank acts as a counterweight and is for example actuated manually and acts as means for shifting the abutment 36. The latter is capable of assuming two positions. In one of these positions (shown in FIG. 3) this abutment stops further advance of the leading edge of the metal sheet before bending, and in the other position (shown in FIG. 1) the abutment 36 is retracted to permit the punches 13 to press the sheet against the anvil 7.

(c) Hydraulic Device C Actuatz'ng the Press A (FIG. 5)

The pipes '8 communicating with the lower part of each of the rams V and the pipes 9 communicating with the upper part are branch connected respectively to a single pipe 39 and a pipe 40 connected to a single distributor L for the whole of the machine. This distributor comprises a tubular body '4 1 closed at both ends. The pipes 39 and 40 are connected to this body 41 on each side of the middle of the latter. A supply pipe 42 supplying liquid under pressure from a pump P communicates with the middle of the body 41 mid-way between the apertures of the pipes 39 and 40 connected to the rams V whereas pipes 43-44 dicharging the liquid into a tank Q are connected to the ends of the body 41 so that the apertures of the pipes 39 and 40 are midway between, on the one hand, the pipes 42 and 43 and, on the other, the pipes 42 and 44.

Slidable within the body 41 is a slide valve 45 having two flanges 46 separated by an annular recess 47 The slide valve 45 is extended at one end by an actuating rod 48.

The slide valve 45 is for example actuated manually and is capable of occupying three positions:

A middle position shown in FIG 5, in which the pipes connected to the rams V are closed and the pipes 43 and 44 shut off from the pipe 42 by the flanges 46. The pistons of the rams V are then held in their inoperative positions;

An extreme left position, in which the liquid under pressure is admitted under the pistons 10 of the rams V which are in their raising stage;

An extreme right position, in which the pressure is admitted above the pistons; the rams V are then in their descending stage.

(01) Hydraulic Device D Actuating the Metal Sheet Feed Device (FIG 6) This device is similar to the device C and comprises similar means designated by similar reference characters carrying the index'number 2: the distributor L to which are connected the pipes 34 and 35 communicating with the ram V pump P and tank Q Supplying liquid under pressure to the pipe 35 produces the displacement of the piston 30 and the rack 28 toward the left, as viewed in FIG. 6, that is, in the direction causing the racks 19 to move away from the presses.

Supplying liquid under pressure to the pipe 34 produces the displacement of the piston 30 and the rack 28 toward the right as viewed in FIG. 6, that is, in the direction corresponding to the advance of the metal sheet t toward the machine.

II. OPERATION OF THE MACHINE Operation of the sheet feed device B will first be described and then that of the presses, followed by description of the formation of a tube.

(a) Movement of the Feed Device B Initially, the switch I is closed and-the switch I consequently open. As the slide valve of the distributor L is shifted toward the shift, the liquid under pressure reaches the left end of the piston 30 of the ram V and shifts it and the'rack 28 toward the right (FIG. 6), resulting in a driving of the gear 27 in the direction of arrow In this direction of rotation the freewheel 26 (FIG. 4) in turn drives the primary plate of the clutch E and the shaft 25 owing to excitation of this electromagnetic clutch. Therefore the gears 24, in rotating in the direction of arrow f drive the racks .19 and the abutments 18 toward the machine (advance). When the rack 28 has reached the end of its travel toward the right (stopped by the adjustable abutment 32), the slide valve of the distributor L is displaced toward the right, which results in supply of liquid under pressure to the right end of the piston 30 of the ram V and a consequent return of the rack 28. During this return, the gear 27 rotates in the direction of arrow P, but owing to the freewheel 26 the gears 24 are not driven and the racks 19 and abutments 18 remain stationary. The piston 30' of theram V moves rearwardly until its rod 31 is stopped by the fixed abutment 33. a

- (12) Movement of the Punches 13 13 of Each Elementary Press The punches are made to rise when the slide valve of the distributor L (FIG. 5) is shifted toward left when when the ram V is at the end of its advance or forward travel. Simultaneously, the slide valve of the distributor L (FIG. 6) is pulled to the right. When the punches 13 13 travel they remain there during the time necessary for maintaining the bending force of the punches applied to the metal sheet to ensure a permanent deformation of the latter. Thereafter, the slide valve of the distributor L is shifted toward the right. The direction of flow of the liquid under pressure in the rams V is then reversed. The liquid under pressure arrives in the upper part of the ram V and is discharged in the lower part. The punches descend. When all the punches have reached the extreme lower end of their travel, the slide valve of the distributor L is shifted toward the left, which causes the metal sheet to advance.

(c) Formation of a Tube (FIGS. 1 and 7 to 12) A tube T (FIG. 12) is formed in two stages; a first stage for bending the rectangular flat sheet of metal t into a semi-cylinder, starting with the leading edge (FIGS.

.7 to 9), and-a second stage for bending the sheet into a second semi-cylinder, starting with the edge of the sheet opposed to the leading edge of the first stage, the two semi-cylinders being interconnected along a median generatrix of the sheet, and the longitudinal edges of the latter being joined to form the lips or edges of a longitudinal joint which is subsequently welded.

(1) First stage.-A rectangular flat sheet of metal t suitably cut to size is placed on the horizontal supports 17 of the feed table in such manner that its rear longitudinal edge is substantiallyin contact with the abutments 18 of the racks 19 'in the initial position of their forward travel. The abutment arm 36 is lowered by the operator who starts up the feed device. As the switch I is closed, the abutments 18 urge the sheet t and cause it to slide along the table, until the ram V reaches the end of its forward travel. At this movement, the leading edge of the sheett encounters the abutment 36 (FIG. 3) which ensures that the rear edge of this sheet is in perfect contact with the two abutments 18 thereby making certain that the leading and rear edges of the sheet are perfectly parallel with the generatrices of the anvil v7.

The slide valve 45 of the distributor L is then pulled to the left to cause the punches 13 and 13 to rise. In the course of this upward travel, the punch 13 in front of which is disposed the abutment 36 raises the latter and causes it to be completely rearwardly retracted owing to the effect of the counterweight or actuating arm 38. At the same time, the punches 13 nearest the frames 2 exert a bending force on the sheet t which bears against the generatrix a of the anvil the most removed from the frames 2 (FIG. 3). The bending force is therefore exerted with a leverage equal to the length l of the segment of sheet engaged under the anvil 7. At the end of the upward travel of the punches, the punches 13 remote from the frames 2 in turn apply the sheet against the anvil 7 and prevent the sheet from moving away from the generatrix a on the anvil. To ensure a permanent curved deformation of the sheet at a radius of curvature corresponding to that of the anvil 7, the punches are maintained a cer- 0 tain period of time in the extreme upper position of their travel, whereafter they are caused to descend simultaneously. When all the punches are in their extreme lower position of their travel, the abutments 18 once more displace the sheet through the same distance. 'The punches thereafter rise and bend a further segment of the sheet, the new bend being connected to the previously formed bend.

Advance of the sheet and the striking of the press succeed one another alternately until the leading edge of the sheet wound the anvil 7 reaches the plate 4. A half-tube has then been formed. The machine and its sheet feed device are then stopped. Closure of the switch I causes the racks 19 and the abutments 18 to return to their initial position. The bent sheet is withdrawn from the machine 7 in a direction parallel with the plane X-X by means of withdrawn from the machine, the sheet is grasped by a j handling machine not shown in the drawings (for example lifting apparatus, carriage or conveyor) and returned to the supports 17 of the table, the previously bent part being disposed adjacent abutments 18 which are mounted in place of the abutments 18. The abutments 18 are higher'than the abutments 18 so as to bear against the generatiix of the bent part of the sheet remote from the machine. These abutments 18" are fixed to the racks 19 in front of the position of the abutments 18 at a distance equal to the length of the sheet bent in the course of the first stage.

After these adjustments, the second tube forming stage proceeds as the first stage. When the tube has been formed, it is extracted from the machine and conveyed to the welding machines.

It will be observed that the leverage of length l for bending the metal sheet is twice as long as that of known presses having a vertical axis in which the sheet bears against that generatrix of the anvil which is on the vertical working axis and is folded on each side of this median generatrix. Consequently owing to this leverage and the inclination of angle x of the axial working plane, the necessary bending force is half that required in known presses. Furthermore, the inclination of the axial working plane X-X permits the sheet to be fed on a horizontal plane, which facilitates handling.

Owing to the multiplicity and the independence of the bending devices and owing to the possibility of a slight staggering in the rising of the different bending devices (those which are fed by the longest pipes 8 being behind those fed by the shortest pipes 8), the power required for the rams V is less than in the case of a single bending device actuated by a plurality of rams in which arrangement the rams in advance are retarded by the late rams. Loss of energy is thus avoided.

HI. PLANT SHOWN IN FIG. 13

If it is desired to produce tubes in a continuous manner, two machines and sheet handling devices could be combined, for example as shown in FIG. 13.

In this arrangement, the fiat rectangular metal sheets 1, suitably cut to size, are brought by a conveyor T having driving rollers to the table of the sheet feed device B of a first machine M having a multiple press A The first stage in the production of the tube shown diagrammatically in FIGS. 7 to 9 is carried out on this machine.

Once bent, the sheet is withdrawn at t in a longitudinal direction relative to the machine M by a tong extractor U carried by a carriage drawn along -for example by a cable. At t the bent sheet is received by a transporting carriage W which carries it in a transverse direction to the feed device B of a second machine M having a multiple press A similar to the machine M The direction of transfer is such that it is the unbent edge remote from the feed device B which is fed forwardly by the device B of the machine M The feed device B is similar to the feed device B except that the thrust abutments for the sheet are higher so as to bear not against the rear edge but against the rear generatrix of the bent part, and these abutments are capable of retracting upon passage of the sheet and standing up again in the known manner. The formed tube T is thereafter extracted from the machine M by an extractor U and then transferred to one of two longitudinal conveyors having support rollers and a driving chain Y. The chosen conveyor conveys the tube to one of two welding stations Z for the purpose of welding the longitudinal edges. The production cycle ceases at this station. In the arrangement shown in FIG. 13, two conveyors Y are shown since the working rate of the machines M and M has been assumed to be twice that of the welding machines Z. It will be understood more conveyors such as the conveyor Y could be used or only one IV. MODIFICATION SHOWN IN FIG. 14

The metal sheets I instead of being fed to the machines M and M in a completely flat state could be fed thereto after their edges have been formed or bent over, these sheets being previously conveyed by the first conveyor T between two pairs of forming rolls having the required profile of known type located on each side of this conveyor. In this case it is necessary to provide a greater height between the lower generatrix a of the anvil and the level of the feed table 17 so as to permit the folded edge of the sheet to engage under the anvil. The feed talble must therefore be lower. It is also necessary to provide support rollers, for example mounted at the end of piston rods of vertical rams or jacks to raise the sheet from the table 17 and bring it in contact with the generatrix a of the anvil once the sheet is engaged under the anvil. The prior folding of the edges of the sheet has the advantage of imparting a better finished appearance to the tubes, but does not modify the tube forming principle.

Although a specific embodiment of the invention has been described, many modifications and changes may be made therein, without departing from the scope of the invention as defined in the appended claims.

Thus the hydraulic devices actuating the punches and feeding the sheets could be automatically controlled by electric control means.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

1. In a machine for bending metal sheets, in which: an automatic sheet feed device feeds the sheets in a longitudinal direction, the sheets moving in a fixed horizontal feed plane: a multiple press comprising a plurality of adjacent elementary presses having: a single stand; as many frames as there are elementary presses, each of said frames being fixed to the stand parallel with the longitudinal direction of the sheets feed and having a swan-neck shape terminating in an upper head so orientated as to face said longitudinal direction, and all the frames being in alignment in a direction perpendicular to said longitudinal direction; a single transverse thin plate rigidly fixed to the heads of the frames and almost completely closing the apertures constituted by said swan-neck shaped frames, said plate having a transverse plane of symmetry which is downwardly inclined relative to the vertical toward the interior of the swan-neck of the frames, and being limited by a lower transverse edge, a single anvil rigidly fixed to the lower edge of said plate below which it is situated, said anvil having an operative face which is downwardly directed and is symmetrical relative to said transverse plane of symmetry; and for each elementary press, a hydraulic actuating device fixed to said stand in front of each frame and an individual bending device op.- eratively connected to said actuating device so that the latter moves the bending device toward the anvil so as to bend the metal sheet, said actuating and bending devices having a same longitudinal axis which is situated in said transverse inclined plane of symmetry.

2. In a multiple press for bending metal sheets in a longitudinal direction for producing tubular elements:

(a) a horizontal feed plane table for feeding metal sheets to be bent;

(b) a plurality of G-shaped parallel aligned frames having apertures;

(c) a single thin transverse plate rigidly secured to the top of said frames in a downwardly inclined position with respect to the vertical, said thin inclined transverse plate almost completely closing the apertures of said C-shaped frames;

(d) a single convex upper anvil rigidly secured to the lower edge of said thin inclined transverse plate and 9 having an inclined plane of symmetry common with said thin inclined transverse plate;

(e) said single anvil having a convex curvature tangent to the feeding plane of metal sheets on a generatrix located on the same side as said horizontal feed plane table with respect to said thin inclined transverse plate;

(1) and a plurality of lower bending dies.

1,437,953 Bailey Dec. 5, 1922 '10 Keller Sept. 7, 1937 Long Nov. 15, 1938 Sheppard Aug. 8, 1939 Rippe Oct. 25, 1960 FOREIGN PATENTS Great Britain June 28, 1935 Sweden July 1, 1958 

